A-43 Free Communication/Poster - Sodium Supplementation/Hydration/Cooling

May 29, 2013, 7:30 AM - 12:30 PM Room: Hall C 304 Board #156 May 29, 9:30 AM - 11:00 AM Sodium Consumption Induces Hyperhydration But Does Not Change Plasma Volume Or Exercise Heart Rate Response Joshua R. Huot, david M. morris, adam jetton, Scott collier, FACSM, alan utter, FACSM. Appalachian State University, Boone, NC. (No relationships reported) Hyperhydration prior to exercise (HPE) in the heat has been shown to improve endurance exercise performance. Possible mechanisms for this ergogenic effect include increases in plasma volume (PV) and improvement in cardiac function. PURPOSE: to measure the PV and heart rate (HR) responses to HPE and exercise in a hot environment. METHODS: Nine male subjects (27 ± 4 yrs, 73 ± 9 kg) completed an exercise test to exhaustion on an electronically braked ergometer to determine VO2 max power output (PMAX). Subjects returned on 3 occasions receiving one of three treatments: 60 mg/kg bm NaCl, (NA), an equal volume of placebo (PL), or no treatment (NT) followed by a 2-hr hydration period in which they consumed water ad-libitum (HP). Immediately following HP, subjects began a 1-hr dehydration ride (DR) at 50% of PMAX at a temperature of 30° C. Nude body mass and blood samples were obtained prior to and immediately following HP, and upon completion of the 1-hr ride. Blood samples were analyzed for PV and changes in NBM were used to calculate hydration status. HR was obtained at minutes 5 and 50 of the 1-hr ride. Data were analyzed using one-way ANOVAs. RESULTS: NA induced a significantly greater rate of HPE (1.1 ± 0.5%) than did PL (0.3 ± 0.4%, P = 0.03) and NT (-0.01 ± 0.6%, P = 0.003) and resulted in lower levels of dehydration following DR (0.7 ± 0.6%) compared to PL (1.3 ± 0.7%, P = 0.045), and NT (1.6 ± 0.4%. P = 0.004). Changes in PV after HP in NA (1.3 ± 5.2%) were not significantly different from PL (-4.4 ± 9.3, P = 0.51) or NT (-1.1 ± 9.5%, P = 0.91). No significant difference in PV following DR were seen between NA (-7.0 ± 8.4%,) and PL (-10.1 ± 6.3%, P = 0.47) or NT (-8.7 ± 10.2%, P = 0.98). No significant differences were observed between treatments with regards to HR at 5 min of exercise (NA = 136 ± 12 bpm, PL = 135 ± 10 bpm, NT = 136 ± 12 bpm, all P > 0.22), HR at 50 min of exercise (NA = 151 ± 13 bpm, PL = 151 ± 11 bpm, NT = 155 ± 12 bpm, all P > 0.86), or increase in HR from 5 to 50 min of exercise (NA = 15 ± 8 bpm, PL = 16 ± 8 bpm, NT = 19 ± 4 bpm, all P > 0.48). CONCLUSION: Although sodium consumption promoted hyperhydration, the increase in body water did not significantly affect plasma volume or exercising heart rates when compared to no treatment or consumption of placebo. Financial support received from ASU URC and RacersReady.com. 305 Board #157 May 29, 9:30 AM - 11:00 AM Sodium Supplementation and Hydration Habits of Ironman Triathletes Luke N. Belval1, Douglas J. Casa, FACSM1, Rebecca L. Stearns1, Evan C. Johnson1, Brittanie M. Volk1, William M. Adams1, Tracey A. Viola2. 1University of Connecticut, Storrs, CT. 2Lake Placid Health Center, Lake Placid, NY. (No relationships reported) An Ironman triathlon challenges both an athlete’s fitness and nutrition practices. Sodium supplementation (SS) is commonly advocated for cramp prevention and sweat-associated sodium loss during training and competition. However, gaps between research findings and real world practice may exist. PURPOSE: To investigate Ironman triathletes’ 1) SS practices, 2) hydration habits, and 3) perceptions on the efficacy and performance benefits of both. METHODS: 161 triathletes were surveyed from the 2012 Ironman World Championships in Kona, HI (IMWC, n=60) and the 2012 Ironman Lake Placid in Lake Placid, NY (IMLP, n=101). Participants had 7.1 ± 6.2 years of experience at Ironman or Half-Ironman distance triathlons. Survey questions targeted hydration and sodium intakes during training and competition. In addition perceived effect of SS in relation to cramping and performance were examined. RESULTS: 72.3% reported changing their drinking habits based on duration of exercise or environmental conditions. 62.7% reported currently taking sodium supplements either during training or racing. 49.0% replied as being “salty sweaters.” Overall, independent of current use, 32.9% responded as having been advised by a coach or medical professional to consume sodium supplements. There were no differences between IMLP and IMWC for changing drinking habits (p=0.787), sodium supplement use (p=0.580), coach or medical advice for SS (p=0.454) or “salty sweaters” (p=0.140). 9.3% reported previous exercise-associated illnesses related to hydration or heat stress. 80% of those who reported these illnesses change their drinking habits based on duration of exercise or environmental conditions, while 53.3% take sodium supplements. Overall, 83.1% either agreed or somewhat agreed with the statement “Sport drinks prevent cramps.” 77.2% either agreed or somewhat agreed with the statement “SS prevents cramps.” 69.1% either agreed or somewhat agreed with the statement “SS improves performance.” CONCLUSION: SS is a common practice for Ironman triathletes and many believe that this reduces incidence of cramps and improves performance. The majority of triathletes also believe that hydration practices should incorporate sport drinks to prevent cramps. Supported by Timex, Inc. 306 Board #158 May 29, 9:30 AM - 11:00 AM Effects Of Sodium Ingestion On Voluntary Water Consumption, Hydration, And Exercise Performance In The Heat David Morris, Josh Huot, Adam Jetton, Scott Collier, FACSM, Alan Utter, FACSM. Appalachian State University, boone, NC. (No relationships reported) Co-consumption of sodium and water prior to exercise tempers dehydration and improves exercise performance in the heat. While this strategy is effective in controlled environments, promoting fluid consumption in unsupervised, non-thirsty individuals is difficult. Thirst can be induced with sodium ingestion via the vasopressin response. PURPOSE: We sought to determine the effects of sodium ingestion on ad-libitum, pre-exercise fluid consumption, hydration, and subsequent exercise performance in the heat. METHODS: Nine male subjects (27 ± 4 yrs, 73 ± 9 kg) completed an exercise test to exhaustion on an electronically braked ergometer (EBE) to determine VO2 max power output (PMAX). Subjects returned on 3 occasions receiving one of three treatments: 60 mg/kg bm NaCl, (NA), an equal volume of placebo (PL), or no treatment (NT) followed by a 2-hr hydration period in which they consumed water ad-libitum (HP). Immediately following HP, subjects began a 1-hr ride at 50% of PMAX, followed immediately by a 200 kJ time trial (TT), both performed on the EBE. Ambient temperature during these periods was 30° C. Fluid consumption and urinary output during HP were measured and used to calculate fluid retention. Nude body mass was measured prior to and at the end of the HP and immediately following the 50% PMAX and TT to determine hydration status. Elapsed time to complete TT was used as a performance measure. Data were analyzed using one-way repeated measures ANOVA. RESULTS: Subjects consumed significantly more water during HP in NA (1380 ± 581 mL) compared to PL (815 ± 483 mL, P = 0.05) and NT (782 ± 454 mL, P = 0.02). Fluid retained at the end of HP was significantly greater in NA (821 ± 367 mL) compared to PL (244 ± 402 mL, P = 0.004) and NT (148 ± 289 mL, P < 0.001). Dehydration rate at the end of the 50% PMAX ride was significantly lower in NA (0.7 ± 0.6%) compared to PL (1.3 ± 0.7%, P = 0.045) and NT (1.6 ± 0.4%. P = 0.004). The TT was completed significantly faster in NA (773 ± 158 s) compared to PL (851 ± 156 s, P = 0.004) and NT (872 ± 190 s, P = 0.006). No significant differences were detected between PL and NT for any of the variables. CONCLUSION: The results suggest that acute sodium ingestion can enhance voluntary fluid consumption leading to hyperhydration and improved exercise performance in the heat. Financial support received from ASU URC and RacersReady.com. 307 Board #159 May 29, 9:30 AM - 11:00 AM Comparison Of Thirst-Driven vs. Programmed Fluid Intake On Half-Marathon Running Performance In Highly-trained Distance Runners Tommy Dion, Audrey Asselin, Eric DB Goulet. University of Sherbrooke, Sherbrooke, QC, Canada. (No relationships reported) A meta-analysis (Goulet, BJSM, 2011) has demonstrated that 1) exercise-induced dehydration (EID) of up to 4% bodyweight (BW) does not impair cycling time-trial (TT) performance and; 2) drinking to thirst optimizes endurance performance (EP). It has long been believed that EID ≥2% BW impairs EP/endurance capacity (Cheuvront et al., CSMR, 2003). No studies have yet tested the impact of EID upon running TT performance. PURPOSE: To compare the effects of thirst-driven (TD) vs. programmed fluid intake (PFI) on half-marathon running performance. METHODS: Following a familiarization trial, 7 highly-trained distance runners (age: 27 ± 8 yrs; weight: 71 ± 3 kg; height: 177 ± 4 cm; VO2peak: 69 ± 4 ml/kg/min) underwent, in a randomized, crossover fashion, 2, 21.1 km running TTs on a motorized treadmill (30°C, 45% RH, facing wind speed adjusted according to running speed) while consuming 3 energy gels (every 6 km) and either drinking water 1) according to thirst sensation (TD) or; 2) to maintain BW loss at 1% (PFI). RESULTS: Subjects were well- and equally-hydrated at their arrival at the laboratory before each experimental trial (urine specific gravity, TD: 1.013 ± 0.008 g/ml; PFI: 1.019 ± 0.009 g/ml, P=0.23). In both trials, volunteers’ total water intakes (TD: 500 ± 251 ml; PFI: 2128 ± 189 ml, P<0.01) were less than their sweat (TD: 2679 ± 232 ml; PFI: 2827 ± 246 ml, P=0.13) and urine (TD: 62 ± 61 ml; PFI: 88 ± 43 ml, P=0.24) losses, thereby producing an EID level of 3.1 ± 0.5% BW (TD) (range: 2.5-3.6% BW) vs. 1.1 ± 0.4% BW (PFI) (range: 0.4-1.6% BW) (P<0.01). Mean rectal temperature (TD: 39.6 ± 0.6°C; PFI: 39.2 ± 0.5°C, P=0.01), perceived exertion (TD: 13.9 ± 1.2; PFI: 13.5 ± 1.0, P=0.05) and perceived thirst (TD: 4.7 ± 0.9; PFI: 3.2 ± 1.4, P<0.01), but not heart rate (TD: 163 ± 15 bpm; PFI: 159 ± 13 bpm, P=0.18), were significantly different between trials. Half-marathon performance times (TD: 88 min 45 s ± 4 min 2 s; PFI: 87 min 46 s ± 5 min 4 s, P=0.43) and running paces (TD: 4 min 19 s ± 20 s/km; PFI: 4 min 15 s ± 24 s/km, P=0.43) were not significantly different between groups. There was no correlation between the changes in EID levels and TT performance times (P=0.84). CONCLUSION: These results suggest that, under a 30°C ambient temperature, both thirst-driven and programmed fluid intake optimize half-marathon running performance in highly-trained distance runners. 308 Board #160 May 29, 9:30 AM - 11:00 AM Effects of 75 Versus 150% Fluid Replacement on Subsequent Morning Hydration Status and 10-km Running Performance Brett A. Davis1, Lauren K. Thigpen2, Jared H. Hornsby3, Mary C. Stevenson2, Pattie L. Riethmaier4, James M. Green, FACSM2, Eric K. O’Neal2. 1Middle Tennessee State University, Murfreesboro, TN. 2University of North Alabama, Florence, AL. 3University of Alabama, Tuscaloosa, AL. 4Old Dominion University, Norfolk, VA. (No relationships reported) PURPOSE: To examine the effects of reasonable but low fluid replacement volume (75% of sweat losses) compared to replacement of 150% of sweat losses as suggested by ACSM guidelines between running bouts on 10-km running performance. METHODS: Well-trained, heat acclimated runners (n = 13; age = 37 ± 12 y; VO2max = 63.3 ± 4.5 ml/kg/min) completed a 75 min of by on a on hot = Following the and in a crossover ± mL) or 150% ± mL) of their sweat losses with a of sport and Participants also consumed a and by the the following runners completed a 10-km time trial by on the the previous = were between and urine specific was RESULTS: and low fluid replacement resulted in a significant difference = in body mass (75% = ± 150% = ± kg) and (75% = ± 150% = ± P < 0.001). heart rates ± vs. ± 12 and were not significantly different > 0.05) between treatments = ± vs. ± = ± vs. ± ± faster (75% = ± 150% = ± P = of perceived exertion was lower = for 150% ± ± trials. Fluid replacement of sweat loss was to intake of a and was to be to maintain running performance and resulted in However, urine and reported in consuming fluid to 150% of sweat losses an fluid intake 150% may be and as as more for Board May 29, 9:30 AM - 11:00 AM And Water Dehydration The University of (No relationships reported) fluid after exercise is as to the of exercise-induced dehydration PURPOSE: compared the of with and water on fluid for a period after EID under hot environment. METHODS: male subjects ± body ± kg; ± ± 4 3 trials. In each trial, they on treadmill for at under hot of ± and 71 ± 4% the subjects at the for one of the drinks and was for No was during equal of the drinks 150% of BW loss were at and min of Blood samples were at and blood samples and urine were also at min and were 5 min prior to each blood RESULTS: the subjects of their BW in all with no significant difference > the end of all subjects were in with fluid being the for < no significant difference was in total volume of drinks consumed > the BW was for ± and but significantly lower for ± < of drinks retained in body was for ± and ± but significantly lower for ± < urine for ± 177 mL) was significantly than ± mL) and ± mL) at the end of < Plasma volume was completed for all with ± and ± being than ± during < No significant difference was in and trials. CONCLUSION: is than and as effective as for following an EID with BW loss under hot environment. Board May 29, 9:30 AM - 11:00 AM Hydration Of A In Runners J. L. A. Eric C. FACSM, FACSM. The State University, (No relationships reported) in hot and environmental sweat rates and may to significant dehydration and in performance. have been on the for years hydration and benefits and performance. The addition of and increases which may in responses that enhance hydration status. To no research has to support the demonstrated any from drinking a with and PURPOSE: compared with was to determine a dehydration when consumed during a running in hot and conditions. METHODS: male runners VO2 = VO2 = body mass = and body = completed at of their VO2max in a temperature and controlled environmental were to 30° C and 50% Subjects were either or water during their and were to consume the subjects were the volume they consumed in the of the Hydration was via plasma and and minutes and body was used to measure sweat rate and fluid retention. RESULTS: sweat rate and fluid consumption for subjects was and mL, body greater fluid when consuming subjects consumed plasma and at and when subjects consumed plasma and at and 60 and at CONCLUSION: with may dehydration for male runners in hot by by Board May 29, 9:30 AM - 11:00 AM Hydration Performance in the Heat N. A. University, 2University of 3University of (No relationships reported) ad-libitum during exercise to dehydration from to of body the effect of fluid losses on repeated cycling performance during in the heat male endurance body performed a cycling on a laboratory The of 3 of 5 km at 50% of max power output and 5 km of Subjects the performance test on occasions and in while drinking water as they or following a drinking km to fluid To the subjects also performed a familiarization the 5 km either in trial at loss or in trial by of body body was for vs. to completion for the of the cycling was in than in the trial by and immediately after the were greater in the than in the Overall, sweat during the was lower in the than in the trial suggested that the hydration improved cycling performance during the repeated in the as to leading to a of dehydration Board May 29, 9:30 AM - 11:00 AM The of and on R. L. FACSM. State University, (No relationships reported) PURPOSE: and during exercise in the heat to maintain and plasma the between dehydration and the of the current is to examine the effects of a and based drinks on and after exercise in a C for METHODS: between the of to for in the current Participants were to exercise on a ergometer in a 50% dehydration of of the body The of rectal and temperature, blood and VO2 were measured after the completion of the exercise time the completion of the subjects were either a or based for the be measured as the time rectal and temperature, blood and this time be as RESULTS: Data demonstrated no significant differences on any between the at the time Participants consumed equal of the and in the of the consuming the significant differences in the for blood and VO2 at the time but not for rectal or temperature CONCLUSION: suggest that the ingestion of a during is not to maintain after exercise in the heat. Board May 29, 9:30 AM - 11:00 AM in the Lake Placid Ironman M. J. FACSM, Douglas J. Casa, FACSM, Rebecca L. K. L. M. University of Connecticut, CT. (No relationships reported) experience a of during an Ironman hydration reduces the of heat is in regards to effect on and lower during a PURPOSE: To examine the relationships between hydration and of and during an Ironman METHODS: Subjects 7 in the Lake Placid Ironman triathlon height: weight: body A of was completed immediately total and was and urine specific and body mass were body mass loss was compared during the with hydration and were by hydration and to compare RESULTS: of and were and by hydration and were and for and were all for and were all and were not significantly The and reported was by of time was not significantly with or body mass loss was significantly with and CONCLUSION: the duration of the the and subjects consumed of fluid for an and were in all hydration groups. reported were and not with Board May 29, 9:30 AM - 11:00 AM And Hydration Status In In FACSM1, FACSM2, University, 3University of and Center, (No relationships reported) PURPOSE: and years of exercise-associated research at in with to the between blood sodium and change in body examine the ambient temperature and hydration and the effect of hydration on performance. METHODS: and body and time were obtained on and was also obtained on a of RESULTS: incidence was by and had a significant with ambient Of the runners with were as change were change to and were change at the There was a significant between and change in body that a lower was more common with all were and were at the There was a significant between change in body and performance in that faster runners to more in body change from to CONCLUSION: incidence can be in in In this is more common with dehydration than and is more common in ambient temperature conditions. loss does not to have an effect on sodium supplementation and fluid ingestion the of thirst Board May 29, 9:30 AM - 11:00 AM Not In In J. J. Douglas J. Casa, FACSM2, 1University of Canada. 2University of Connecticut, Storrs, CT. (No relationships reported) The incidence rate of heat to in both and The of is the that should take as as after the of in treatment is have rates of and a greater of related to is treatment via To is the of in treatment on rate in PURPOSE: To examine the effects of a in treatment on and responses prior and following treatment in individuals during exercise in the heat. METHODS: on a treadmill in the heat an rectal temperature Participants were in the heat for either a 5 20 or and were in a water at returned to Heart rate and were measured while blood was measured 5 min during the and at 2 min during RESULTS: There were no differences in immediately prior to ± ± ± rates during water were all ± ± ± and were by times ± ± Mean was exercise ± ± ± 12 and following each period 75 ± 73 ± ± 5 CONCLUSION: We that in treatment of individuals results in and in treatment up to min for individuals with is an effective and treatment The was by Board May 29, 9:30 AM - 11:00 AM Of Hyperhydration And On Performance In And David Adam James University of 2University of University, (No relationships reported) can of the seen during endurance performance in the increases in temperature Hyperhydration has been shown to increase sweat enhance reduces body heat To the no research has both PURPOSE: To determine 10 cycling time trial performance in the heat can be improved by the of and by the to exercising in an environment. the and the exercise was METHODS: 5 reported to the laboratory to 10 TT 50% on with hyperhydration both or was a and via water ± for 20 or placebo was in all with being by plasma volume levels blood The was via performance completion blood and measures were mass and urine were and blood samples were obtained at any and immediately exercise to using with repeated measures were RESULTS: performance time ± was significantly by than than and than increase from to 10 TT was significantly less for and than C and There was no significant difference between and exercise levels the 4 24 = P = CONCLUSION: of was or endurance performance in hot and Board May 29, 9:30 AM - 11:00 AM and Following J. R. University Of Canada. (No relationships reported) and of University of Canada. guidelines for the of heat not differences which affect treatment In has been suggested that body body mass may be a temperature rates during water following exercise-induced PURPOSE: We the of on rectal temperature rates during water following exercise-induced METHODS: male were a ± or ± Participants on a treadmill in the heat an Following exercise and a were to the of the in a water at returned to temperature was measured RESULTS: time was greater for compared to ± vs. ± = the rate of was greater for compared to ± vs. ± = 0.02). CONCLUSION: The current results suggest that individuals with a low body body mass take to during water following exercise-induced is to examine guidelines for the treatment of heat should differences between Supported by

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